Speaker box dimensions

Ok so I recently purchased a 94 Honda Accord and I  wanted to transfter my speaker box from my old car to it, but I can't because it is too wide.  I asked my dad to make me a new box but he said he can't just trim the dimensions because it will effect sound quality.  He does not use computers at all so he refuses to sit and read all the stuff about it (he's very anti-computer), and I dont understand anything that I read about subwoofer boxes.  I have tried to figure out how to use those calculator programs, but I dont know where to find the information to input.  So I was wondering if someone could here help me by telling me what dimensions to make the box if I supplied all of the other information.  I have two 12 inch Pyramid Super Blue Subwoofers, on the back of them it says the following... 600 watt, 4 ohm, SPL 95 dB, 50 oz. magnet and the product number is 1254US.  Also I am not sure if my amp information is important or not, but I will supply some just in case... I have a 800w Pyramid amplifier it is about 10in x 12in.  If more information on the amp is needed just let me know.  I would a sealed box unless something else is recommended as better.  Thanks in advance!!

http://www.pyramidcaraudio.com/itempage.asp?model=PW1254US

there is a link to the woofer. The item manual link is also available there. Most good woofers will give you the recommended box specs. Since im guessing you got yours at a pawn shop or walmart, they arent decent enough to come with box specs. Not to say you cant make them sound halfway decent. Easiest way is to use a box building software program and mess around with the different dimensions you can use. By the way, how big is your current box and what kind is it? ported im guessing?

Okay... Thanks for responding!

I would like for the speaker box to not take up my entire trunk like it did in my old car.  My current speaker box is 11x38x29 it almost fits into my car, it just doesnt sit flat on the floor and it hangs over onto the back seat when its folded down... I originally wanted my dad to just trim a few inches off each side but he said that is a no no for sound quality.  So basically it needs to be smaller that those dimensions. And yes it is a ported box.

Also I downloaded a program and with help of the manual  (duh) I was able to put almost all of the things it asked for in.  Just a few things... Is QE on the manual the same thing as Qes on the program? and same for QT and Qts... and on the manual the Pmax field is empty, I am assuming that is the max wattts, 600? and it asks for diameter.. is it asking for the subwoofer diameter from edge to edge? coil diameter or what?  I am kinda confused on that.  And one last thing.... the program I downloaded is just for one sub per box, can anyone recommend a program that help with a 2 sub box?

Thanks in advance for your help, I am pretty confused when it comes to this stuff but i think i am making some progress.

And I didnt ask for your criticism, I asked for help and I don't really care to hear your opinion unless it is helpful.. and yours was NOT.

The reason I was inquiring about the one or two speaker box was because all of the ones the program generates are too small for two speakers and I dont know how to change it.

Well I was going to help you but you obviosly show no respect to others on this site. Mustangfoo simply was pointing out that your current box is atleast twice as big as it should be and your dad obviously has no idea what he is doing if he thinks it is currently built for SQ. Unless you change your attitude up quick I think youll find that calling those who are taking time out of their day to respond to your topic "morons", I imagine you will find your logon quickly blocked by the moderators/admin.

I took his post as criticism--he said "lol" twice, so I thought he was laughing at me, and by asking a question like is it in cm I thought he was poking even more fun.  Then he made fun of the kind of speakers I have.  I never said I particularly liked them, I am just trying to work with what I have.  I am not interested in spending tons of money on a sound system, I just want something better than what I have now.

As far as my current box being twice the size needed... I have no idea, thats why I am here.  My dad did not make it he just wouldn't alter because he knows that its not a good idea.

I am sorry if I offended anyone but when someone offends me, that is how I react.  I honestly dont think I did anything wrong, as far as I am concerned mustangfoo is to blame because he made fun of the subs I have.